Spitzer detects comet storm in nearby solar system

October 20, 2011

This artist's conception illustrates a storm of comets around a star near our own, called Eta Corvi. Evidence for this barrage comes from NASA's Spitzer Space Telescope, whose infrared detectors picked up indications that one or more comets was recently torn to shreds after colliding with a rocky body. Image credit: NASA/JPL-Caltech

(PhysOrg.com) -- NASA's Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the "Late Heavy Bombardment," which may have brought water and other life-forming ingredients to Earth.

During this epoch, comets and other frosty objects that were flung from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust.

Now Spitzer has spotted a band of dust around a nearby bright star in the northern sky called Eta Corvi that strongly matches the contents of an obliterated giant comet. This dust is located close enough to Eta Corvi that Earth-like worlds could exist, suggesting a collision took place between a planet and one or more comets. The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.

"We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system," said Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and lead author of a paper detailing the findings. The findings will be published in the Astrophysical Journal. Lisse presented the results at the Signposts of Planets meeting at NASA's Goddard Space Flight Center in Greenbelt, Md., today, Oct. 19.

Astronomers used Spitzer's infrared detectors to analyze the light coming from the dust around Eta Corvi. Certain chemical fingerprints were observed, including water ice, organics and rock, which indicate a giant comet source.

The light signature emitted by the dust around Eta Corvi also resembles the Almahata Sitta meteorite, which fell to Earth in fragments across Sudan in 2008. The similarities between the meteorite and the object obliterated in Eta Corvi imply a common birthplace in their respective solar systems.

A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of cometary bodies. This bright ring, discovered in 2005, looms at about 150 times the distance from Eta Corvi as the Earth is from the sun. Our solar system has a similar region, known as the Kuiper Belt, where icy and rocky leftovers from planet formation linger. The new Spitzer data suggest that the Almahata Sitta meteorite may have originated in our own Kuiper Belt.

The Kuiper Belt was home to a vastly greater number of these frozen bodies, collectively dubbed Kuiper Belt objects. About 4 billion years ago, some 600 million years after our solar system formed, scientists think the Kuiper Belt was disturbed by a migration of the gas-giant planets Jupiter and Saturn. This jarring shift in the solar system's gravitational balance scattered the icy bodies in the Kuiper Belt, flinging the vast majority into interstellar space and producing cold dust in the belt. Some Kuiper Belt objects, however, were set on paths that crossed the orbits of the inner planets.

The resulting bombardment of comets lasted until 3.8 billion years ago. After comets impacted the side of the moon that faces Earth, magma seeped out of the lunar crust, eventually cooling into dark "seas," or maria. When viewed against the lighter surrounding areas of the lunar surface, those seas form the distinctive "Man in the Moon" visage. Comets also struck Earth or incinerated in the atmosphere, and are thought to have deposited water and carbon on our planet. This period of impacts might have helped life form by delivering its crucial ingredients.

"We think the Eta Corvi system should be studied in detail to learn more about the rain of impacting comets and other objects that may have started life on our own planet," Lisse said.

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12 comments

So you don't know how scientists date objects, and then you say it's an assumption only because you don't understand?

You are an idiot. I don't understand how a website like this can constantly attract the worst of the internet as time goes on, this is just becoming unbearable.

If you had the mental capacity to go to google and search for an answer you'd have been able to learn how they do it. One of the most obvious methods being radiometric dating, a concept even high schoolers manage to be aware of.

kevinrts - your credibility is really shot. Most of the things you call assumptions are actually easily measured using very standard, well-established techniques.

We can measure crater dates from photos. Easily. A large percentage of the large ones in the solar system date to between 800 million and one billion years after the sun formed. What on earth would YOU call such an event? Late-heavy bombardment certainly works for me.

I am so tired of your anti-science, pro-creationist agenda I could scream. You do not belong here. You do not have anything like an open mind, nor do you contribute anything. You are easily refuted by science taught in grade school.

You can measure the age of a star simply by examining its spectra. No assumptions needed. Unless you're suggesting that elements fuse differently at different places. In that case, though, the universe would be a far wackier place to live.

I like the idea of being able to observe such natural phenomenon. It would be best if they could use some type of motion sensor camera attached to the instrument to record the bombardment while it is actually happening. Too bad they didn't add one on Spitzer.

@kevYours is a nice fairytale. Please take it with a big grain of salt. Better still, simply reject it.

All the rest about thousands of years and heavy godder bombardment is simply speculation of the first order - all inferred from scribbles of ignorant goat herders in the desert.

Just how do you know that the Earth is about 6000 years old? Was someone there to record its creation for us and leave us with a scientific record? NO. So where does the age come from? Assumptions. Wholly unsubstantiated.

It is little wonder this article will attract flakes like a low wage 'discount' store. The gist of this is that life as we know it here originated in just this way. Therefor, finding a process so similar going on in a place so close to home is literally inductive proof that life is the umbiquitous mundane resident of normal solar systems; and that most if not all stars have, did have, or will have planets and processes similar to those that generated our system....and....us! Of course that would fly in the face of unreasoning religious dogma for the violation of which many scientists in past ages had been put to death. This multidimensional multiverse has ample place for God, and locally 'calculated' ages for our place in the universe are kind of silly. Life that God created permeates the universe bringing life to all receptive planets eventually. The fact of his creation of it is not mocked. We have neighbors! Get over it! They are our brothers too!

IF there was a God (Supreme Being, Creator of all), I would think that he would live in a different dimension that we, as yet, have not discovered. You might even call that dimension, for want of a better name, the "undiscovered country". He would have the ability to travel from his own dimension into OUR dimension and would have that ability because of vast knowledge of matter and energy, even all possible science. All knowing, he could have come to Earth a million years ago and visited the Sumerians, Egyptians, Mayans, and many other cultures on Earth and taught them different sciences. Certainly, the Sumerian art describes the worship of alien giants by the ancient peoples of that land. The Bible describes, in Ezekial, an encounter with alien beings who had strange ships coming down from the "heavens". There are too many instances of these kind of encounters in so many cultures that there has to be some truth to it. God, or gods are extraterrestrials or from another dimension.

They may not be the God or gods of the Jewish, Christian, or Muslim Bibles, but they may exist whether or not we can see them. They would not have been able to leave anything of substance behind to PROVE their existence because they are not of this dimension. In their dimension, there most likely would be substantial evidence that they live. But that evidence does not necessarily cross through that membrane which divides our dimension from theirs.So, it could be that believers are wrong, and yet they are right also. The problem lies in the fact that humans, for all their present technology, still haven't perfected the study of science. There is too much that we DON'T KNOW, and yet, we imagine that we know it all. That makes us into egotistical fools. Even atheists think they know for certain the nonexistence of God or gods. They also are foolish in their absolute certainty, because they really know NOTHING of the sort and are just presuming. I will wait until all the data is in.

True; but that's not a licence to make shit up. Why do you write rambling bad sci-fi about other dimensions and the Sumerians, and then claim to be waiting for the evidence to come in? By the way, atheism is simply the lack of belief in gods. Few would claim to know absolutely. One can be both athiest (don't believe, there's no evidence) and agnostic (don't know absolutely, because it's an unfalsifiable claim).